1. Field of the Invention
The present invention relates to video monitoring, and more particularly towards a system and method for monitoring slab filler machines.
2. Discussion of the Prior Art
A typical slab filler machine includes a number of slabs arranged in rows forming a belt. Each slab includes a number of cavities for accepting a pre-determined number of tablets per cycle. The number of cavities per row defines the number of tablets simultaneously dispensed. These tablets, such as medication or vitamins, are dispensed into a container, automating the process of filling containers with the pre-determined number of tablets. However, slab filler machines lack methods for ensuring the desired number of tablets are dispensed into each container. For example, the slab filler machine cannot account for random events, such as a broken or missing tablets, thus a given container may include less than the desired (pre-determined) number of tablets.
Current methods of quality control are not robust or accurate. Further, some systems may require modification of the slab filler machines. These modifications are generally not well received by manufacturers. Further, modifications may not work with all tablets. For example, for a method where tablets are backlit and the presence of light indicates a missing tablet, holes are drilled through each cavity of a slab. However, the accuracy of the system may be affected when used with translucent tablets, and the robustness of the method may be affected when used with tablets which may fall through the holes.
Currently, no quality control method exists for monitoring slab fillers in conjunction with the variety of tablets on the market. Therefore, a need exists for a robust and accurate system and method of monitoring slab filler machines.
The present invention relates to a method for monitoring a slab filler machine. The method includes grabbing a dispensing frame from a dispensing side of the slab filler, and classifying a plurality of cavities in the slab filler according to a correlation between the dispensing frame and at least one template.
The method localizes the cavities in the dispensing frame prior to classifying the cavities. The method normalizes the dispensing frame prior to classifying the cavities.
A plurality of slabs can be monitored simultaneously.
The method further comprises the step of initializing a layout of the slab filler. Initialization the layout includes determining a number of columns including cavities on the slab filler, and determining a number of rows including cavities on the slab filler. Initialization also includes determining a difference between the dispensing frame and a discharge frame grabbed from a discharge side of the slab filler, a significant different indicating an active cavity, a non-significant different indicating a plugged cavity. The position of each cavity in each frame is determined based on a projection in the x-axis of the slab filler and a projection in the y-axis of the slab filler.
According to an embodiment of the present invention, an apparatus is provided for monitoring a slab filler machine including a plurality of cavities. The apparatus includes a first camera with a view of a dispensing side of the slab filler, a second camera with a view of a discharge side of the slab filler, and a compare module receiving a frame from each camera, the compare module which localizes the cavities in each frame and compares each cavity to at least one template.
According to an embodiment of the present invention, a method is provided for monitoring a slab filler machine. The method includes grabbing a dispensing frame from a dispensing side of the slab filler, and grabbing a discharge-frame from a discharge side of the slab filler. The method further includes classifying a plurality of cavities in the slab filler according to a correlation between the dispensing frame and at least one template, and classifying the plurality of cavities in the slab filler according to a correlation between the discharge frame and the template.
The method localizes the cavities in each frame prior to classifying the cavities. The method normalizes each frame prior to classifying the cavities.
A plurality of slabs can be monitored simultaneously.
The method includes initializing a layout of the slab filler. Initialization comprises determining a number of columns including cavities on the slab filler, determining a number of rows including cavities on the slab filler, and determining a difference between the dispensing frame and the discharge frame, a significant different indicating an active cavity, a non-significant different indicating a plugged cavity. The position of each cavity in each frame is determined based on a projection in the x-axis of the slab filler and a projection in the y-axis of the slab filler.
The method applies a search window to each cavity prior to classifying, wherein the search window is at least the size of the template, and determines a correlation coefficient for at least one template position within the search window. The method further includes determining a correlation coefficient between the template position and a full template, and determining a correlation coefficient between the template position and an empty template. The method determines a highest correlation coefficient between determined correlation coefficients, and assigns a class corresponding to the highest correlation coefficient to the cavity in the search window. The method includes comparing the highest correlation coefficient to a pre-defined threshold to determine a tablet state within each cavity. The tablet state is one of present, missing, and broken.